RegistryAccess UnauthorizedAccessException

Question

 this is the code to set  Registry full  Access and  ther is an UnauthorizedAccessException

 i need to have  access read and write for evey user that login to the server

with out changing   registry   permissions  group policy

 

SecurityIdentifier sid = new SecurityIdentifier(WellKnownSidType.WorldSid, null);

NTAccount account_demo = sid.Translate(typeof(NTAccount)) as NTAccount ;   (> Option)

NTAccount account = new NTAccount(Environment.UserName);

using (RegistryKey rk = Registry.LocalMachine.OpenSubKey(key))

  {

RegistrySecurity rs = new RegistrySecurity();

 RegistryAccessRule rar = new RegistryAccessRule(

account.ToString(), RegistryRights.FullControl, InheritanceFlags.ContainerInherit | InheritanceFlags.ObjectInherit,

PropagationFlags.None,AccessControlType.Allow);

rs.AddAccessRule(rar);

rk.SetAccessControl(rs);

}

}

 

               }